​Summit Snow Sampling Science Explained (by and for a Layperson)

by James Holmes

Some family and friends have asked, why exactly are you there again? What are you trying to achieve by taking snow samples on Mt. Everest? As we idle around base camp again, waiting for good health and clear weather for a summit attempt, let me take a shot at answering this.

The reason we are sampling the snow and looking for black carbon (or soot) is fairly simple. It’s based on the principle that darkly colored things absorb sunlight and then heat up rapidly, whereas lightly colored things reflect sunlight and heat a lot less rapidly. Pure white snow is highly reflective and melts slowly. Dirty snow with relatively more black carbon absorbs more heat, melts more quickly, and contributes to receding glaciers. This is the primary effect.

There is also a secondary effect. The same light/dark principle also affects climate change. As glaciers recede, they expose rock that is darker than the snow. On the large scale, less ice and more rock will absorb rather than reflect sunlight and contribute to warming of the planet.

There it is. Simple. Darker snow means less ice and warmer climate.

Once back in the U.S., the samples can be analyzed to see how much black carbon is in the snow and where it comes from, whether industrial activity, fuel burning, agricultural burning, cook stoves, etc.